Vegetable materials such as wood, reed, bamboo, cane and the like which are or can be used for the preparation of fibrous materials are composed of several basic parts. In general, fibrous vegetable matter is made up of about 15 to 30 percent lignins and extractives, such as resins and the like, with the remainder of the about 70 to 80 percent being carbohydrates. The carbohydrate portion of the fibrous vegetable matter is about 10 to 30 percent hemicellulose with the remainder being cellulose, and the cellulose portion of the carbohydrate is about 45 to 55 percent alpha cellulose and about 5 percent other celluloses, all percentages being expressed on a wood basis.
As is well known, one of the first steps in conventionally converting fibrous vegetable materials to fibers for use in the preparation of paper or paper-like materials is a pulping process. The primary goal of the process is to remove most of the lignins from the fibrous vegetable material and separate the remaining carbohydrate fibers into individual fibers. In all known pulping processes, such as kraft, sulfite and others, when efforts are made to remove substantially all of the lignin from the vegetable fiber mass, a major part of the hemicellulose is lost, and the remaining cellulose and hemicellulose fibers are chemically and/or mechanically damaged. This results in a significant loss of yield and a major reduction in strength of paper or paper-like products due to fiber damage. For example, in a kraft pulping process, the normal yield known in the art is about 45 percent by weight. But, if only the lignins and extractives were removed from the fibrous vegetable material, the yield obtained would be 70-80 percent.